The present invention relates to a mobile type auto-doffer, for doffing a plurality of full bobbins from a row of spindles mounted on a spinning machine or a twisting frame and the like, for mounting full bobbins onto a row of pegs disposed between a spindle rail of the machine and a surface of the floor of the spinning plant, for dismounting the same number of fresh bobbins mounted on that row of pegs, and for donning fresh bobbins onto the row of spindles, wherein conveyance of full bobbins after being doffed and conveyance of fresh bobbins to be donned can be both carried out simultaneously.
Generally, a row of pegs is disposed at the region underneath the spindle rail of the spinning machine. Therefore, when the above-mentioned doffing and donning operations are carried out, it is necessary to move the doffing head with cop holders and to move the donning head with other cop holders vertically as well as horizontally. When conveyance of full bobbins after the doffing operation and conveyance of fresh bobbins before the donning operation are carried out simultaneously, it is also necessary to select moving vertical passages for the doffing and donning heads such that one passage is disposed at the outside region of the other passage, so that when the heads are being moved vertically as well as horizontally, there is no chance for one head to obstruct the movement of the other head. Due to this requirement for moving the doffing and donning heads, all of the present auto-doffers of this type use vertically moving members which move along vertical shafts disposed on both sides of an auto-doffer. Furthermore, on such moving members, a doffing or donning head is slidably supported and horizontally guided, so that either head can be moved toward or away from the spindle.
One doffer of this type is shown in Japanese Patent Application Laid-open No. Sho 51-139934 (Japanese Patent Application No. Sho 50-63433). The doffing or donning head of this type of doffer has two extended legs, which are disposed at both end portions of either head, respectively, in such a way that both legs are perpendicular to the head. In addition, rack teeth are provided on each of the two legs. Therefore, when turning a pinion rotatably mounted on a vertically moving member, either head can be moved horizontally because the pinions are caused to mesh with the rack teeth on the legs.
Another doffer of this type is shown in Japanese Patent Application Laid-open No. Sho 51-112935 (Japanese Patent Application No. Sho 50-37883). A doffing or donning head of this type of doffer also has two extended legs, which are also disposed at both ends of either head, respectively, in such a way that they are perpendicular to the head. Furthermore, two follower rollers are provided on the legs at the rear ends thereof, respectively. During the time when the head is moving vertically, the head can also be moved horizontally due to the guidance of the slanted surfaces on the vertical plate cams, because the follower roller is always in contact with the slanted surface by urging the roller upon the slanted surface by means of a spring. The legs of the head of the doffing device are disposed in such a way that such legs are arranged outside of the legs of the other head of the donning device, or vice versa.
One drawback of these types of auto-doffers is that, due to the arrangement of the legs as mentioned above, the required longitudinal length of the doffer becomes inevitably long. With respect to the width of the doffer, such width tends to also be quite long, because within such width the long leg must slide horizontally along the horizontal guide of the vertical moving member and in a direction toward as well as in a direction away from the spindle. Accordingly, this wide doffer sometimes creates difficulties if used with spinning machines, because the doffer must be moved along a narrow alley situated between the adjacent spinning machines. Another drawback is due to the fact that since the head having such a long leg is always hanging over from the front end of a support for the leg, difficulties are caused when the head is being rested correctly at its given position. Accordingly, quick doffing as well as quick donning cannot be expected. In addition, the smooth movement of the leg moving within the horizontal guide is reduced when fly waste accumulates in the horizontal guide.
If the driving system of the doffing or donning device is a mechanical driving system which uses gears, racks, pinions, screws, etc., to convey the turning movement of a motor to the movement of the heads, it is necessary then to combine such a mechanical system with a complicated electrical controlling means for resting the heads correctly at their given positions. However, as a result of this requirement the construction of the doffer becomes inevitably complicated, and the possibility of operational failures occuring is therefore increased. Furthermore, the size of the auto-doffer is enlarged, thereby causing the maintenance and control of the doffer to be difficult. Due to these drawbacks, the above-described auto-doffers cannot yet be practically used in a spinning mill.
An object of the present invention is to provide an auto-doffer with an overall small size and a light weight. Furthermore, it is also an object of the present invention to accelerate the doffing operation as well as the donning operation.